Code

        private void imgToString(string imgPath)
        {
            FileStream fs = new FileStream(imgPath, FileMode.Open);
            BinaryReader br = new BinaryReader(fs);

            byte[] imageBuffer = new byte[br.BaseStream.Length];
            br.Read(imageBuffer, 0, Convert.ToInt32(br.BaseStream.Length));
            string textString = System.Convert.ToBase64String(imageBuffer);
            fs.Close();
            br.Close();
        }
        private void stringToImg(string imgString)
        {
            byte[] img = System.Convert.FromBase64String(imgString);
            MemoryStream ms = new MemoryStream(img, true);
            ms.Read(img, 0, img.Length);
            Image imge = Image.FromStream(ms);
        }